Electrical relay arrangement



July 12, 1932. L. M. SIMPSON ELECTRICAL RELAY ARRANGEMENT Filed Jan. 20, 1930 Imam? L am: e ZFZ' Y FEE Patented July 12, 1932 UNITED STATES PATENT OFFICE LANGELOT MARTIN SIMPSON, OF THORNEIR, 'NEAR LEEDS, ENGLAND, ASSIGNOR TO ASSOCIATED TELEPHONE' AND TELEGRAPH COMPANY, OF CHICAGO, ILLINOIS, A

CORPORATION OF DELAWARE ELECTRICAL RELAY ARRANGEMENT Application filed January 20, 1930, Serial No. 421,969, and in Great Britain April 16, 1929. I

The present invention relates to electrical relays and is more particularly concerned with improved arrangements for permitting a plurality of relays, in addition to operat- C ing electrical contacts, to control one anlay controls an interlocking member by means of which the subsequent operation of the relay which initiates the hunting operation is prevented until said relay has de-energized following the de-e'nergization of the test relay. 1 A further feature of the invention is tha in a subscribers rotary line switch for use in telephone systems the operation of thecutoff relay on an incoming call completes a circuit for the line relay and operates a mechanical stop to prevent the movement of the line relay armature, the engagement of this armature with the stop serving to prevent the stop returning to its normal position until the line relay has de-energizedn These features and others notspecifically mentioned at this point will be better under- I stood from the following description of one method of carrying the invention into effect which should be taken in conjunction with the accompanying drawing. This shows the invention applied to a subscribers rotary line switch of the homing type as used in automatic telephone systems. It will be understood, however, that the invention is not limited to this particular application and that it may be employed advantageously under a number of other conditions such as will readily occur to those skilled in the art.

- v Referring now to the drawing, Fig. 1 shows a. front view and Fig. 2 shows a side viewof a subscribers line and cut-ofi' relays pro vided with the mechanical interlocking arrangement according to the invention while Fig. 3 shows details of the circuit arrangement of the line switch with which the relays are associated.

Referring now particularly to Figs. 1 and 2-, the relays are mounted in known manner the end of the relay core and renders the relay slow acting. a

The interlocking is effected by a bell crank lever 14 which is shown more clearly in Fig. 1 and which is pivoted to the front plate 15 by means of the screw 16; The shorter limb 17 of the lever 14 engages with an. extension 18 of the armature 19 of the lower relay,

while the longer limb 20 is notched as shown for engagement with the pawl 21 which is an extension of armature 22 of the upper relay. The pawl 21 which is more clearly shown 1n Fig. 2 is pivoted by means of the screw 23 sothat it normally rests underthe influence of gravity against the small top screw 24 which rides in a convenient slot cut in the end of the pawl. i

It must be mentioned that the pivot screws 16 and 23 are provided at-their heads with a boss on which the lever and pawl may turn, and this boss is of slightly greater length than the thickness of the lever or pawl, so that the pivot screws can be screwed up tightly without affecting the free movement of the lever and pawl.

When both relays are in the non-operated position both the lever 14 and the pawl'2l areheld by gravity inthe position shown in the drawing, i. e. with the pawl arm slightly higher than the end of the longer limb 20 of the lever 14, and if the circuit operation is such that the upper relay is now energized, the armature 22, which is pivoted by means 7 of the tongues 25 let into'suitable slots in the base plate 10, will now fully operate, thereby carrying with it the pawl 21 into a position just above the V shaped notch in the end of the lever 14. If now the lower relay is energized the'movement of, the associated 2o. pawl wilL come into engagement with, the lever and the; armature 22; will only bev able to move a. distance depending upon the adencountered.

armature 19 will move the lever 14 owing to the engagement of the extension 18 with the shorter limb 17 of the lever. By this means the longer limb 20 will be raised a proportionate. distance thereby carrying with it the pawl 21 which. it will. beremembered was moved into a position over the V shaped notch in the end of the lever 14 due to the operation 035 armature 22- of thou-pp'er relay;

-Hence when theupper rel-'ayis subsequently de-energized the armature 22 will return to its normal position owing to the pressure exerted by the contact springs 26', and by this means the pawl21 will be causedto ride over the V shaped notch so that it drops by gravity over the end of the lever against the stop screw 24.

In this position the pawl isnow opposite the end; of the lever 1.4. and, assuming now that. the upper relay is again; energized, the

] ;l1StII1I1i3.0i said; lever. This distance may of. course be: sos-mall as to prevent the contactsprings from operating, at all. Further- .more, in case; the lower relay should be released meanwhile, the pressurefiexertedby the paw-l 21. against the end of the lever 14:. will be sufilcien-t to hold the lever in its operated positionindependent of. the condition of. the lower relay, so that by this meansthe upper relay may be rendered. in-operative throughoutits; energization at this stage; It will be noticed-fromthe drawingthat the lower edge of. the pawl arm; is shown bevelled sothat it anay; ridemore easily over. the V shaped. notch position over the \I -shapednotch-ini theil'ever.

Line relay L at armatures Z and Z closes a clrcuit for the rotary magnet DM which can be traced. over theinterrupter springs I,

armature k armature private wiper P and the homeposition contact in lts. bank,

- armature-Z toearth. The-rotary magnet DM is operated and steps; the switch: until an unearthed} contact on. the privatew-iper P is During the stepping; the switching relay K. is short-circuitedjas follows: earth, over. private. wiper P, armature Z armature-k relay. K,,home1 position contact. of wiper; Hi to earth over private conductor 1?. Theswitching; relay K operates when, a tree. trunk. is. found I thus causing; the lever to lift the. pawl. in the.-mannenalready described. Relay K at armatures I0 and opens the original energizing circuit of relay L, at armature k closes a point in the circuit of private conductor P, at armature 70., prepares a circuit for the meter M and at armature 76 closes a point in a circuit for relay L. Relay L releases after a suitable slow period, due to its copper slug and as the armature moves into its normal position, the pawl is caused to ride over the end of the V-shaped notch so that it drops into its normal position.

Moreover, upon the full release of relay L earth via the resting armature oi Z will then be extended by way of the now operated armature in to the winding of relay L, and accordingly relay L. again becomes energized, but. is; prevented from operating atthis stage owing to the pawl coming into engagement withthe end of the lever which is held up by? relay K.

lVhen, however, the subscriber receives a call, the switching relay K is energized befor the line relay L due to the extension of earth over the private conductor P, and infthis'case the lever is lifted before the circuit is completed to the line relay L. Hence, upon the tulk operation of relay K, line relay L will. become energized over the circuit previously'traced, but. operation of the armature wilLbe-prevented. owing to the action ofthe pawl andlever.

Suppose now that the system is arranged for calling-party release and that the calling subscriber clears before the called-subscriber,

relay K of the called subscribersv lineswitch will be released upon the removal of earth from the private-conductor P when the switch train. is dropped, and although it will be observed. that. the circuit. to relay L is opened atyarmature 70;, the relay holds under the infiuencerof the copper slug until an alternative circuitis closed: by way of the subscribers loop and; the now resting contacts of arma- By this means it will be apturesic and k preciatedfrom thepreviousdescription. of the, interlocking, arrangement, that relay L will: be prevented from operating during. this condition, and therefore. the needless operation of the lineswitch and the selection of an outgoing. line is prevented.

Assuming that the called subscriberv clears before the calling subscriber, on the subsequent. release of the calling subscriber, relays K and Lwill de-energize and there will be no f'urthercircuit completed for relay L.

Such afeature is of particular utility in a register controller system where not only wouldthe lineswitch be operated, but regis ter equipment would be needlessly occupied, thus necessitating the provision of this equipment in larger quantities than would othertion unnecessarily and their life must be definitely shortened.

Claims:

1. In a relay arrangement, a first and a second relay, an armature for each of said relays, an interlocking lever controlled by the armature of said first relay, a pawl member controlled by the armature of said second relay, means for energizing said first relay to move its armature and operate said interlocking member, means for energizing said second relay to move its armature and operate its pawl into engagement with said interlocking member, and means for deenergizing said first relay to restore its armature only, said pawl preventing the release of said interlocking member.

2. In a relay arrangement, a first and a second relay, an interlocking member controlled by said first relay, a pawl member controlled by said second relay, means responsive to the energization of said first relay for operating said interlocking member, and means responsive to the energization of said second relay for operating said pawl member into engagement with said interlocking member and for maintaining said interlocking member in its operated position after said first relay is deenergized.

3. In a hunting switch for telephone or like systems having access to a plurality of trunks, a test relay for controlling the hunting operation of said switch to select one of said trunks, a line relay for initiating the huntin operation, an interlocking member controlled by said test relay, means responsive to the energization of said test relay before said line relay for operating said interlocking member to prevent said line relay from initiating the hunting operation when it energizes, and means responsive to the deenergization of said line relay after said test relay has deenergized and released said interlocking member for again energizing said line relay to initiate the hunting operation of said switch.

4. In a subscribers rotary lineswitch for use in telephone systems, a cut-off relay and a line relay each having an armature, an interlocking member controlled by said cut-ofl relay armature, means responsive to an incoming call to said lineswitch for energizing said cut-off relay to move its armature to operate said interlocking member and to complete an energizing circuit for said line relay, said interlocking member engaging said line relay armature to prevent its movement after said line relay energizes, and means on said line relay armature for preventing the release of said interlocking member after said cut-ofi"' relay has released its armature until said line relay has deenergized and released its armature.

5. In a subscribers rotary lineswitch for telephone systems having access to a plurality of trunks, a line relay having contact springs for initiating the trunk hunting operation of said switch, a test relay for controlling said hunting operation, means responsive to an outgoing call from said lineswitch for energizingsaid line relay to operate its contact springs to initiate the hunting operation of said switch, means for energizing said test relay when a tree trunk is found and for deenergizing said line relay, a circuit connection completed by said test relay through the contact springs of said line relay for again energizing said line relay, and means controlled by the operation of said test relay for preventing the operation of said contact springs at the time said line relay is again energized.

6. In a relay arrangement, a first and a Second relay, a pivoted interlocking member controlled by said first relay, a second pivoted member controlled by said second relay, means responsive to the energization of said first relay for operating said interlocking member to prevent the operation of said second pivoted member when said second relay is energized, means when said second relay is energized for holding said second pivoted member against said interlocking member and maintaining it in its operated position after said first relay is deenergized, and means if said second relay is initially energized for operating said second pivoted member to ride over the end of said interlocking g member and after said interlocking member is operated by the energization of said first relay and said second relay deenergizes, restores to its normal position, said interlocking member thereafter acting as a stop to prevent further operation of said second pivoted member.

7. In a relay arrangement, a first and a second relay, an armature on each ofsaid relays, an interlocking member controlled by the armature of said first relay, a pawl member controlled by the armature of said second relay, means for energizing said first relay to move its armature and operate said interlocking member to a position opposite said pawl member, means for energizing said second relay to attempt to move its armature, the movement of said second relay armature being prevented by said pawl member engaging said interlocking member, said pawl member maintaining said interlocking mem her in its operated position after said first relay has deenergized and released its armature, and means when said second relay is energized first and then said first relay is energized for operating said pawl and inter-' locking members without any effect on the respective movements on said armatures.

In testimony whereof I afiix my signature.

LANCELOT MARTIN SIMPSON. 

